Marriage is an important health-related role in the lives of most people. Married men weigh more and are more often obese than unmarried men, while marital status is not a predictor of women's weight when other variables are controlled. Obesity is increasing in prevalence in the U.S., and opportunities for prevention of obesity may be linked with marriage. This project will examine relationships between marriage and obesity, extending previous epidemiological analyses to identify how rapidly and under what conditions weight changes occur after marriage, analyze factors contributing to weight changes with marriage, and examine attitudes and beliefs about weight and marriage. The analyses will address fundamental issues in social epidemiology and medical sociology, including differentiating the direction of causality, evaluating timing of marital role changes in the life course, and examining social support. The project will include two integrated components, as follow. 1. Analysis of existing data sets will address issues not examined in prior studies. The National Longitudinal Survey (NLS) includes yearly body weights from 1981-1995 that provide annual time series data to examine the direction of influence of both weight on marriage and marriage on weight. The 1988-1994 NHANES III data provide current cross-sectional data on marriage and weight that will be compared with earlier NHANES I and II and 1961-1962 NHES I data to describe trends over time. 2. A qualitative investigation will examine a sample of adults over time to provide an in-depth analysis of how they experience marriage and weight. These interviews will be used to provide insights for interpreting quantitative findings from the other portion of the project, and to generate new insights about marriage and obesity. Together these components will complement each other to provide new knowledge and understanding about marriage and weight that can be used to develop interventions to prevent and manage obesity.